Tick, Tick, Boom

2. About 10-12 days after hiking in the Appalachian Mountains, this young woman presents with a 7-in circular rash on her upper back that is slightly warm to the touch. She denies fever, pruritus, and joint pain.

^{Source: Paul Whitten / Science Source [Image number BZ4987]}

Diagnosis: Lyme disease is the most common tick-borne illness in the United States, with more than 25,000 confirmed cases in 2014. It is concentrated mostly in the northeast and upper Midwest, although in 2014, only five states (Colorado, Hawaii, Louisiana, New Mexico, and Oklahoma) reported no incidence. Lyme disease is caused by Borrelia burgdorferi, which is transmitted to humans by the Ixodes tick.

For more information, see “Beyond the bull's eye: Recognizing Lyme disease.” J Fam Pract. 2016;65(6):373-379.